Lua/Custom player ability

One of the most useful aspects of Lua scripting in SRB2 is the ability to give characters entirely new gameplay mechanics. This tutorial will provide you with knowledge on how to use basic Lua hooks to add new abilities.

Making a double jump with the AbilitySpecial hook

Start a new Lua script (in any text editor of your choice) and paste the following into it:

addHook("AbilitySpecial", function(p)

end)

First, we only want this script to run if the player is using Sonic, so we'll add the following:

addHook("AbilitySpecial", function(p)
    if p.mo.skin == "sonic" then

    end
end)

Next, the jump should be able to be used once. We'll check if the player has already used their ability with the PF_THOKKED player flag.

addHook("AbilitySpecial", function(p)
    if p.mo.skin == "sonic" then
        if p.pflags & PF_THOKKED then
            return true
        end

    end
end)

Now, if the player has already used the double jump and presses jump again, the script will exit.

addHook("AbilitySpecial", function(p)
    if p.mo.skin == "sonic" then
        if p.pflags & PF_THOKKED then
            return true
        end

        p.pflags = $ | PF_THOKKED
    end
end)

Finally, we will set the player's z momentum. Unlike most other games, Sonic Robo Blast 2 uses the z axis as the upwards direction.

addHook("AbilitySpecial", function(p)
    if p.mo.skin == "sonic" then
        if p.pflags & PF_THOKKED then
            return true
        end
        P_SetObjectMomZ(p.mo, 10*FRACUNIT, true)
        p.pflags = $ | PF_THOKKED
    end
end)

The boolean true determines if the momentum is relative to the player's existing vertical momentum, which also corrects for their scale.

But that's not all, there are many other hooks out there. See Lua/Hooks for a complete list.